Blow up the balloon, and then let it deflate to stretch out the latex/rubber. This makes it easier to fill!
Insert a funnel into the neck of the balloon.
Step 3: Add cornstarch and water to the balloon
Add the cornstarch into the funnel.
Cornstarch doesn't like going through the funnel, so you may need to use a pen or stir stick to poke it through.You can also add one small spoonful at a time and shake it down.
Once all the cornstarch is in the balloon, pour in the water.
It might take a minute for the water to fully absorb into the cornstarch and go through the funnel.To help with this, pinch the neck of the balloon then push it down into the cornstarch to make more room for the water.
Step 4: Tie the balloon closed
Squeeze out as much air as possible and tie the balloon into a knot, close to the cornstarch and water.
Knead the balloon until the cornstarch and water are fully mixed.
Trim off the balloon neck, cutting just above the knot. (optional)
Your oobleck stress ball is complete!Squeeze it and knead it to feel the super fun texture!